I use Firefox on Ubuntu.
I installed espeak.
When I use Narrate, Firefox reads a text with robotic espeak voices.
I installed Mbrola with french voices.
I can use espeak + mbrola on cli:
espeak -v mb/mb-fr1 "parlez vous français ?"
And get more realistic voices.
But firefox only uses espeak voice.
How to force Firefox narrate to use Mbrola voices?